My Joomla cache is enabled and if i change something in k2 element i must everytime delete cache, it's any way to set in joomla if i save k2 element then delete cache?

Hi. Joomla! caching has many layers. When you save an item the component cache of K2 is being cleared. But there are also, the cache of the modules, the page cache etc which are not cleared. So you first need to find what type of cache are you talking about. If for example it's a module cache you can set it to expire sooner.